The copper-inducible ComR (YcfQ) repressor regulates expression of ComC (YcfR), which affects copper permeability of the outer membrane of Escherichia coli

Mermod, Mélanie; Magnani, David; Solioz, Marc; Stoyanov, Jivko V (2012). The copper-inducible ComR (YcfQ) repressor regulates expression of ComC (YcfR), which affects copper permeability of the outer membrane of Escherichia coli. BioMetals, 25(1), pp. 33-43. Oxford: Springer Netherlands 10.1007/s10534-011-9510-x

Preview

Text 10534_2011_Article_9510.pdf - Published Version Available under License Publisher holds Copyright. Download (510kB) | Preview

The pathway of copper entry into Escherichia coli is still unknown. In an attempt to shed light on this process, a lux-based biosensor was utilized to monitor intracellular copper levels in situ. From a transposon-mutagenized library, strains were selected in which copper entry into cells was reduced, apparent as clones with reduced luminescence when grown in the presence of copper (low-glowers). One low-glower had a transposon insertion in the comR gene, which encodes a TetR-like transcriptional regulator. The mutant strain could be complemented by the comR gene on a plasmid, restoring luminescence to wild-type levels. ComR did not regulate its own expression, but was required for copper-induction of the neighboring, divergently transcribed comC gene, as shown by real-time quantitative PCR and with a promoter-lux fusion. The purified ComR regulator bound to the promoter region of the comC gene in vitro and was released by copper. By membrane fractionation, ComC was shown to be localized in the outer membrane. When grown in the presence of copper, ∆comC cells had higher periplasmic and cytoplasmic copper levels, compared to the wild-type, as assessed by the activation of the periplasmic CusRS sensor and the cytoplasmic CueR sensor, respectively. Thus, ComC is an outer membrane protein which lowers the permeability of the outer membrane to copper. The expression of ComC is controlled by ComR, a novel, TetR-like copper-responsive repressor.

Interest & Impact

Downloads

321 since deposited on 04 Oct 2013
82 in the past 12 months

Citations

5 Citations in Web of Science ®
6 Citations in Scopus

Search

in Google Scholar™

Services

Actions (login required)

Edit item

Actions (login required)

Edit item